1. Field of the Invention
This invention relates to a magnetic latent image scanning device for a magnetic printing machine which includes a rotary magnetic recording drum, and magnetic recording head arranged to be moved along the axial direction of the magnetic recording drum and fed with video signals to be processed. The relative movement between the magnetic recording drum and the magnetic recording head in the peripheral direction of the magnetic recording drum constitutes the primary scanning, while the relative movement between the magnetic recording drum and the magnetic recording head along the axial direction of the magnetic recording drum constitutes the secondary scanning. This invention is directed to a magnetic printing machine most suitably applied to a magnetic copying machine in which video signals obtained by image pickup from a document are recorded as the latent image on the recording drum by the magnetic head, and the latent image is developed, transferred and fixed for obtaining a copy. Thus, more particularly, the a magnetic printing machine is most suitably applicable to a record portion of the magnetic duplicator by which numerous copies can be automatically and speedily obtained from one document.
2. Description of the Prior Art
A magnetic copying machine is known, in which video signals obtained by image pickup from a document are recorded as a magnetic latent image on a recording drum by a magnetic head.
In the magnetic copying machine or particularly in a magnetic duplicator by which numerous copies can be obtained rapidly, the rotational speed of the recording drum should be increased, and a multichannel head should be used, in order to shorten the time taken to form the latent image. However, when a multichannel head is used, there is a problem with cross talk between channels. Accordingly, the spacing between the adjacent tracks is limited to a certain value.
I have proposed a recording head mechanism to solve the above problem, as shown in the U.S. Pat. No. 4,072,957. In the recording head mechanism, plural channels are arranged in the axial direction of the recording drum, shifted from each other in the peripheral direction of the recording drum. In such a manner, the spacing between the channels is increased to some extent, although the spacing between the scanning loci of the heads is small. Such an arrangement is suitable for recording alphanumeric and Japanese "kana" syllabary figures, on say a, 9.times.7 dot matrix. However, when a high resolving power such as about 10 lines/mm is required as in a magnetic duplicator or a Chinese character printer, the above arrangement becomes complicated. The machanism is expensive, and requires numerous adjusting steps.